Physicochemical evaluation of composts produced from coffee pulp and some locally available organic matterat Dale District, Ethiopia

Composting is proved to be environment friendly effective management option for the increasing volume of coffee wastes generated and causing significant environmental degradation in developing countries. In view of this, the quality of composts produced from coffee pulp with locally available organic matter following the windrow method was examined based on four treatments in randomized complete block design (4x3). The study involved determining some physicochemical parameters at 25, 55 and 80 days of composting. Mean values of bulk density, moisture content, pH, electric conductivity, organic matter, total organic carbon, total nitrogen, total phosphorous, total potassium and carbon to nitrogen ratio ranged from 483.6 kg/m –487.11 kg/m3, 50.74%–52.43%, 7.45-8.36, 3.08 mS/cm-3.42 mS/cm, 45.26%-46.99%, 26.19%-27.27%, 1.54%-1.61%, 0.41%-0.59%, 0.75%-1.15% and 17.5-18.44, respectively. Bulk density, total nitrogen, total phosphorous and total potassium increased with composting time in contrast to moisture content, organic matter, total organic carbon and C/N. pH and electrical conductivity initially increased but decreased at final stage. Mean physicochemical parameters of matured composts fell within the range of acceptable limits set by different countries guidelines. All parameters were not significantly different (p>0.05) except moisture content, pH and total potassium as compared to within treatments (p<0.05). The results revealed that a mixture of 50% coffee pulp,20% cow dung, 20% enset leaf and 10% top soil is more preferable to produce quality compost and consequently protect the environment.